<html>
<script>
function print(id){
	console.log( "hello: " + id);
}

function start(){
	print("Jerry");
	inject();
	print("Jerry");
}

function inject(){
	var oldFunction = print;
	print = function(id){
		oldFunction(id);
		console.log("post");
	};
}
start();
</script>
</html>